I read the article on kinetic bombardment. Evidently was is required are telephone-pole, 9 ton+ tungsten rods with fins and a guidance system. The shape minimizes air resistance, and tungsten is hard to burn. Downside: the guidance system would likely burn up after entering the atmosphere. (The other downside being to get these 9+ ton tungsten rods in orbit to begin with.)
telephone-pole-shaped
The project was colloquially referred to as “Rods from God”.